I just installed the Vishnu/Harman Motive system on my E92. I love the sound and the new found power. My question to all you, is that when I down shift(6MT) from 3-2 I hear a strange noise, almost like a "jake brake" sound. As soon as the clutch is fully engaged it goes away, if I match the revs it does not make the sound. Any ideas?

I love the new system, my car sounds like a sports car now, not a 328.